Eavesdropping optimization for quantum cryptography using a positive operator-valued measure
Howard E. Brandt · Physical Review A · 1999
It is demonstrated that the eavesdropping optimization obtained recently by Slutsky et al. [Phys. Rev. A 57, 2383 (1998)] for Bennett's two-state protocol of key distribution in quantum cryptography holds, not only for the case in which an ordinary von Neumann projective measure is implemented by the legitimate receiver, but also for the case in which a positive operator-valued measure is implemented, as in Brandt et al. [Phys. Rev. A 56, 4456 (1997)]. In both cases, identical expressions hold for both the Renyi information gained by the eavesdropper and for the error rate induced by the eavesdropper in terms of the parameters characterizing the key distribution system and the eavesdropper's probe.